Ok.
Dont think anyone said what it would need to repair the bike.
The bike would need to be stripped down. Then cleaned. The frames Black. That would have to be removed on the drop out. Since its a part of the frame that holds the wheel and the gear mech. It has to be held in alignment. As if the drop outs are squint, you might have trouble getting the wheel in. Or trouble breaking axles. Or trouble with gear selection.
Then the welding would need to be done. Ive heard of a product called Lumiweld. I dont know if its suitable for bike frames. I dont think normal hobby type ARC or MIG welding machines are able to weld alloy. So you may need to get a TIG machine. Or some one thats got one and is capable of welding alloy.
Then when the weldings done. The welds would have to be dressed back acurately. So that theres still enough metal to be strong. And so the gear hanger and the wheel fits in properly.
Then the frame would need repainting in the area.
It would be a lot of work. By skilled craftsmen.
If this was a week old frame, that was under a guarentee. It might get fixed. But I think they would just replace it.